1. Field of the Invention
This invention relates to devices used for removing needles and needle/sheath combinations from hypodermic syringes and, preferably, for safely disposing of said needles or needle/sheath combinations.
2. Discussion of the Prior Art
Hypodermic needles can act as serious sources of infection if proper care is not taken during their removal from syringes and during their disposal. Needles are often difficult to remove from syringes after use and there is always a danger that health field workers (doctors, dentists, assistants, nurses, etc.) may accidentally puncture their hands, which significantly increase the risk of infection.
The risk of accidental puncture has been reduced (but not completely eliminated) by the common practice of providing a safety sheath or cap which envelopes the needle at all times except when the sheath is removed so that an injection may be given. Once the sheath has been re-positioned after use, the risk of accidental puncture is much reduced, but the user may still be exposed to contaminated fluids when the needle/sheath combination is removed from the syringe. For example, the inner end of the needle, i.e. the part that connects to the syringe, is not covered by the sheath and in many cases has a sharp needle-like projection for extending into the dose chamber of a syringe. The exposed inner end may be contaminated with a patient's fluids because of the tendency of fluids within the needle to flow backwards to the inner end due to the suction generated as the needle is removed from the syringe.
Devices for removing needles and needle/sheath combinations from syringes are already known. For example, Canadian Pat. No. 1,184,547 issued on Mar. 26, 1985 to Frontier Plastics (South Wales) Limited discloses a device in the form of a closed container having a keyhole shaped slot in its top wall. The slot accepts standard sized hypodermic needles and, by drawing the needles into the narrow part of the slot and pulling back on the syringe, the needles are detached and fall into the body of the container. However, needles often do not detach easily from syringes and must often be twisted or rotated relative to the syringe barrel. This is of course essential if the syringe is of the type which has a screw-threaded hollow projection onto which the removable needles are screwed. The device mentioned above does not facilitate this action (the needle may rotate in the slot and a free hand must be used to hold the container) and the needles, once removed from the syringe barrel, may be jammed in the slot and have to be freed by hand. All of this increases the risk of contamination and reduces ease of use.
Throw-away removal devices are also known, e.g. the device disclosed in U.S. Pat. No. 4,610,667 issued on Sept. 9, 1986 to Pedicano et al. This is a funnel shaped device having a closable cap for the enlarged end. The syringe and needle is inserted through the enlarged end into the narrow section where the needle is gripped using one hand and removed as the syringe is twisted and pulled back with the other. The needle remains in the device and the cap can be closed and the whole unit thrown away. Such devices are however bulky to store and expensive to use because each device is good for only one use.
Other disposable devices are shown in U.S. Pat. Nos. 4,430,082 issued to Schwabacher on Feb. 7, 1984 and 4,559,042 issued to Votel on Dec. 17, 1985, but these devices allow the user to contact the inner end of the needle as it is removed from the syringe.
Accordingly, there is a need for an improved device for removing needles or needle/sheath combinations from hypodermic syringes.